Haptic planning for bones fracture surgery

Background

The aim of orthopaedic trauma surgery is to restore the anatomy and function of displaced bone fragments to support osteosynthesis. For complex cases, including pelvic bone and multi-fragment femoral neck and distal radius fractures, preoperative planning with a CT scan is indicated. The planning consists of: 1) fracture reduction – determining the locations and anatomical sites of origin of the fractured bone fragments, and 2) fracture fixation – selecting and placing fixation screws and plates. The current bone fragment manipulation, hardware selection, and positioning processes based on 2D slices and a computer mouse is time-consuming and requires a technician.

Purpose

A 3D haptic-based system for patient-specific preoperative planning of orthopaedic fracture surgery based on CT scans to assist surgeons in planning complex orthopaedic trauma surgeries.

Methods

We have developed a new system for patient-specific preoperative planning of orthopaedic fracture surgery based on CT scans. The system provides the surgeon with an interactive, intuitive, and comprehensive, planning tool that supports fracture reduction and fixation. Its unique features include: 1) two-hand haptic manipulation of 3D bone fragments and fixation hardware models; 2) 3D stereoscopic visualization and multiple viewing modes; 3) ligaments and pivot motion constraints to facilitate fracture reduction; 4) semi-automatic and automatic fracture reduction modes; 5) interactive custom fixation plate creation to fit the bone morphology.

Results

We evaluated our system with two experimental studies: 1) accuracy and repeatability of manual fracture reduction; and; 2) accuracy of our automatic virtual bone fracture reduction method. The surgeons achieved a mean accuracy of less than 1mm for the manual reduction and 1.8mm (std=1.1mm) for the automatic reduction. We conclude that 3D haptic-based patient-specific preoperative planning of orthopaedic fracture surgery from CT scans is useful, accurate, and may have significant advantages for evaluating and planning complex fractures surgery.